The Yukon Arctic Ultra is a series of non-stop multiday races that take place concurrently beginning in Whitehorse, Yukon at the beginning of February each year.
The marathon, 100/300/430 mile races follow the course of the Yukon Quest.
The longer races have three disciplines: mountain bike, xc-skis or foot.
The race is billed as the toughest ultramarathon in the world where the temperatures can drop to –40 °C (–40 °F) plus wind chill.
While the organizers provide trail guides, there is a real risk of frostbite and amputations.